The disclosures herein relate generally to organ preservation systems and more particularly to an organ preservation system including articles comprising a super-coolable composition having long-duration phase change capability.
It is common for a donor organ for a transplant procedure to be removed from a donor at one facility and to be transported to another facility where a transplant recipient is awaiting the transplant procedure. Often, such facilities are at distant locations relative to each other. To minimize degradation of the donor organ during transportation, the donor organ is generally transported using an organ transportation apparatus that maintains the organ in a chilled state and that provides for perfusion of an oxygenated and nutrient-balanced solution (hereinafter referred to as the perfusion liquid) through vessels and/or cavities of the donor organ.
Maintaining the donor organ in the chilled state provides several advantages relative to the viability of the donor organ in the transplant procedure. One advantage is that maintaining the donor organ in the chilled state lowers the metabolic activity of the donor organ""s, thus reducing the demand for physiologic oxygen levels and consumption of nutrients. Another advantage is that by assisting in lowering the metabolic activity of the donor organ""s cells, the rate of production of by-products of metabolism such as carbon dioxide and lactic acid is reduced, thus reducing tissue damage and stabilizing the pH level and osmotic balance of the perfusion liquid. Yet another advantage is that the demand for oxygen in reduces, thus protecting against inadequate oxygen levels that can result in ischemic tissue.
To maintain the donor organ in the chilled state, it is common for the donor organ to be contained in an insulated organ container, for the perfusion liquid to be chilled and/or for the entire organ preservation system to be contained in an insulated organ preservation system container. The insulated organ container and the insulated organ preservation system container include provisions for maintaining the donor organ contained therein in the chilled state for a period of time. Chilling of the perfusion liquid is accomplished by a number of techniques, including circulating the perfusion liquid through a heat exchanging device and providing a reservoir of chilled perfusion liquid in an insulated container.
Passive-type insulated containers include insulating material for reducing the rate of heat transfer between contents therein and an ambient environment. Other than such insulating material, no other means is provided for maintaining an item contained therein in a particular thermal condition. Active-type insulated containers include insulating material and a climate preservation implement. The climate preservation implement is capable of actively maintaining a volume of the container at a particular thermal condition. Powered cooling devices and conventional thermal masses (e.g. freezable cold packs, ice blocks, etc.) are examples of climate preservation implements.
Conventional insulated containers, thermal masses and techniques for cooling the perfusion liquid suffer from several limitations that impair their ability to maintain the donor organ in the chilled state for an extended period of time (e.g. as long as 50 hours) during transport. Examples of such limitations include a limited time duration that conventional thermal masses can maintain a frozen/chilled state, the degree of super-cooling achievable by conventional thermal masses, the effectiveness of conventional passive-type insulated containers, the limited time a portable power supply can sustain the operation of a powered cooling device and the operating efficiency, weight and space associated with such powered cooling device.
In many ways, these limitations have a significant adverse affect on organ transplant procedures and organ donation in general. Examples of such adverse affects include impairing the physiological condition of a donor organ, limiting the selection of donor organs to a particular organ recipient, limiting the scheduling predictability for surgical teams and limiting the feasibility of a world-wide network of organ donors and organ recipients. Accordingly, an organ preservation system that at least partially overcomes limitations associated with maintaining a profusion fluid and a donor organ in a desired chilled state during transport of the donor organ is useful.